Avery Products - Avery - Print or Write Mailing Seals, 1in dia., White, 600/Pack - Sold As 1 Pack - Ideal for sealing flyers, brochures and newsletters. - Perforated seals make opening easy without damage to mailer. - Permanent adhesive ensures secure closure. Ideal for sealing flyers, brochures and newsletters. Perforated seals make opening easy without damage to mailer. Permanent adhesive ensures secure closure.